package cn.yanweijia.slimming.utils;

/**
 * Created by weijia on 08/10/2017. <br/>
 * 图像处理类
 *
 * @author weijia
 */

public abstract class YUV420SPUtils {
//    public static int decodeYUV420SPtoY(byte[] yuv420sp, int width, int height) {
//
//        if (yuv420sp == null) return 0;
//
//        int yuv_y = 0;
//        for (int j = 0, yp = 0; j < height; j++) {
//            for (int i = 0; i < width; i++, yp++) {
//                int y = (0xff & ((int) yuv420sp[yp])) - 16;
//                if (y < 0) y = 0;
//                yuv_y += y;
//            }
//        }return yuv_y;
//    }

    /**
     * 内部调用的处理图片的方法
     */
    private static int decodeYUV420SPtoRedSum(byte[] yuv420sp, int width, int height) {
        if (yuv420sp == null) {
            return 0;
        }

        final int frameSize = width * height;
        int sum = 0;

        for (int j = 0, yp = 0; j < height; j++) {
            int uvp = frameSize + (j >> 1) * width;
            int u = 0;
            int v = 0;
            for (int i = 0; i < width; i++, yp++) {
                int y = (0xff & ((int) yuv420sp[yp])) - 16;
                if (y < 0) {
                    y = 0;
                }
                if ((i & 1) == 0) {
                    v = (0xff & yuv420sp[uvp++]) - 128;
                    u = (0xff & yuv420sp[uvp++]) - 128;
                }
                int y1192 = 1192 * y;
                int r = (y1192 + 1634 * v);
                int g = (y1192 - 833 * v - 400 * u);
                int b = (y1192 + 2066 * u);

                if (r < 0) {
                    r = 0;
                } else if (r > 262143) {
                    r = 262143;
                }

                if (g < 0) {
                    g = 0;
                } else if (g > 262143) {
                    g = 262143;
                }

                if (b < 0) {
                    b = 0;
                } else if (b > 262143) {
                    b = 262143;
                }

                int pixel = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);
                int red = (pixel >> 16) & 0xff;
                sum += red;
            }
        }
        return sum;
    }

    /**
     * 对外开放的图像处理方法
     */
    public static int decodeYUV420SPtoRedAvg(byte[] yuv420sp, int width, int height) {
        if (yuv420sp == null) {
            return 0;
        }
        final int frameSize = width * height;
        int sum = decodeYUV420SPtoRedSum(yuv420sp, width, height);
        return (sum / frameSize);
    }
}
